The present invention is in the field of selector switches.
Typically switches used for selecting one of a plurality of modes will make a different electrical connection for each of the modes. On the other hand, potentiometers, whether a rotary dial or linear slide, are typically used to provide amplitude control over a continuously changing signal. The potentiometer gives the user the ability to make adjustments over a continuous range of amplitudes for the signal. The potentiometer knob may be interengageable with physical detentes at various locations in the potentiometer travel to mark off various levels of the signal. The user is thus given a physical feedback as the size of the signal is changed.
In accordance with an embodiment of a method of the invention, an input is obtained from a range of continuous analog signals. Each of a set of discrete selections is assigned a specified range of analog signals. Each range is separated from an adjoining range by a guard band of signals. A sector indicator is a variable having a value indicative of one of the discrete selections to be selected by the switch. The sector indicator is initialized. An input analog signal is received and a determination is made as to whether the input analog signal is within one of the specified ranges of analog signals. If so, the sector indicator is set to correspond to the specified range. Otherwise, the sector indicator is not changed. The sector indicator may be used to illuminate one of a plurality of lights to give the user feedback indicating which sector has been selected.
According to an apparatus embodiment for performing the method, a potentiometer and a state machine are employed to achieve a selector switch. The state machine sets the sector indicator and only changes the sector indicator when the signal from the potentiometer crosses into the specified range for a sector having a different sector indicator. No change is made to the sector indicator while the potentiometer produces an output signal corresponding to a guard band.